"sample 207 T2 key"
CHEMISTRY 207 SAMPLE TEST QUESTIONS KEY 1. Circle the correct answer. a. Which one of the following does not have resonance structures? b, Which one of the following has a square pyramid shape? c. Which one of the following molecules has a net dipole moment. The shape of the molecule is given below in parentheses. CF4 CH4 SO2 BH3 (tetrahedral) (tetrahedral) (bent) (trigonal planar) d. Which of the following is probably NOT a stable compound PH3 MgO MgF3 Li2O e. Which of the following molecules has the biggest dipole moment? H2 HF BrCl IBr f. Which one of the following molecules does NOT have a net dipole moment. The shape of the molecule is given below in parentheses. SF4 BF2Br CO2 NF3 (see-saw) (trigonal planar) linear (trigonal pyramid) g. Which one of the following has sp3 hybridization on the central atom? h. Which of the following ions is most likely to be stable. (Hint: consider the Lewis structures) NH NH2 NH3 NH4 i. Which of the following molecules has a Lewis structure similar to that of N2? CO H2 O2 Cl2 j. What is the formal charge on the sulfur atom in the figure on the right? +1 -1 0 -2 k. Which of the following bonds is least polar? HF ClBr CF OF 1 CHEMISTRY 207 SAMPLE TEST QUESTIONS KEY l. Including the one shown on the right, how many resonance forms can be drawn for PO43- O O P O O 2 3 4 5 m. Which one of the following is linear? n. How many orbitals are there a set sp hybrid orbitals? 2 3 4 5 o. Which of the following molecules has a net dipole moment BF3 FCCF CCl4 ICl3 trigonal planar linear tetrahedral T shaped p. Select the molecule in which the central atom violates the octet rule BF3 NH3 CO2 PH3 q. Which of the following is a planar molecule CH4 BH3 NH3 PCl5 r. A molecule with sp3d hybridization on the central atom always has a trigonal bipyramid geometry always has five pairs of electrons or bonded atoms around the central atom always has five bonds on the central atom always is a non planar molecule s. The angle between the H-N-H bonds in NH3 is closest to o o o 90 109.5 o 120 180 t. Which of the following is the balanced net ionic equation for the precipitation of calcium phosphate when aqueous solutions of sodium phosphate and calcium chloride are mixed . 2Na3PO4(aq) + 3 CaCl2(aq) 6 NaCl(aq) + Ca3(PO4)2(s) 2 PO4(aq) + 3 Ca(aq) Ca3(PO4)2(s) PO4(aq) + Ca(aq) CaPO4(s) 6 Na(aq) + 2PO4(aq) + 3Ca(aq) +6 Cl(aq) 6 Na(aq) + 6 Cl(aq) + Ca3(PO4)2(s) u. Which one of the following is an acid base reaction? 2 HCl + Mg H2 + MgCl2 HCl + KOH H2O + KCl C(s) + O2(g) CO2(g) S8(s) + 4 Cl2 (g) 4 S2Cl2(l) v. Which of the following salts is insoluble in water? FeCl3 Na2CO3 Pb(NO3)2 Mn3(PO4)2 2 CHEMISTRY 207 SAMPLE TEST QUESTIONS KEY w. In which of the following molecules does Mn have an oxidation number of +6. MnS KMnO4 K2MnO4 MnO2 x. Which of the following reactions is NOT a redox reaction? Cu(s) + F2(g) CuF2(s) K2SO4(aq) + BaCl2(aq) BaSO4(s) + 2KCl(aq) 2HCl + Mg(s) H2(g) + MgCl2(aq) C(s) + O2(g) CO2(g) y. Which of the following is a fusion reaction? 7 4 Be 0 1 7 Li 3 3 2 He 1H 4 He 0 1 2 1 222 86 Rn 218 84 Po 4 He 2 1 0 n 235 92 U 137 52 Te 97 40 Zr 20 n 1 z. The reactions in nuclear reactors can be best characterized as Fusion Fission Alpha decay Gamma decay aa. In the reaction 27 13 Al ? 24 11 Na 4 He , the missing particle must be a(an) 2 alpha particle beta particle neutron positron 232 bb. Th undergoes alpha decay. The decay product undergoes a beta decay. What is the product of the second decay? 228 228 232 228 Rn Ac Ac Th cc Which of the following types of materials is most dangerous if ingested Alpha emitters Beta emitters Gamma emitters x-ray emitters dd What is the missing product for the fission reaction shown below 236 92 U 142 56 Ba + 91 36 Kr + ? three protons three neutrons An alpha particle A beta particle ee. The half-life for decay of 3H is 11 yr. How many years must pass to reduce a 16.0 gram sample to 2.0 g. 11 yrs 22 yrs 33 yrs 44 yrs ff. If an isotope is above the belt of stability in the plot of number of neutrons vs. number of protons then the isotope will most likely decay by electron capture beta emission positron emission alpha emission gg. Which one of the following is a ( antibonding) orbital? 3 CHEMISTRY 207 SAMPLE TEST QUESTIONS KEY hh. Which one of the following statements is TRUE? Bond length tends to decrease as bond strength increases Bond length tends to increase as bond strength increases Single bonds tend to be shorter than double bonds Triple bonds tend to be longer than double bonds __________________________________________________________________________ A B C D a. Which of the diagrams above corresponds to a molecule with a triple bond? __D____ b Which of the diagrams above corresponds molecule with no net bonds? ___C_____ c. Which of the diagrams above could correspond to a N2 molecule? ____D____ d Which of the diagrams above corresponds to a paramagnetic molecule? ____B____ e. Which of the diagrams above corresponds to a molecule with a double bond? __B____ f. Which of the diagrams above corresponds to a molecule with a single bond? __A____ 2. Fill in the blank a. How many grams of Na are in 10g of NaOH? molNaOH molNa 22.99gNa 10gNaOH 40g 5.75g NaOH molNaOH molNa -1 b. How many moles of NaCl are in 100 mL of 2 M NaCl (0.100L)(2 mol L ) = 0.2 mol c. The molecule HCN contains _2 bonds and 2_ bonds. d. How many moles of hydrogen atoms are in ten moles of Ca(OH)2 ___10x2 = 20 23 e. How many S atoms are in two moles of S2Cl2 __2x2x6.02x10 __________ f. Give the approximate values of the angles shown in the figure on the right _109.5___, __120___ 4 CHEMISTRY 207 SAMPLE TEST QUESTIONS KEY h. 10 mL of a 2.5 M NaCl solution contains __0.025________ moles of NaCl i. For CrO4 the oxidation numbers are _+6_ for Cr and __-2___ for O 92 What is the missing isotope in the following reaction 36 Kr 236 92 U 141 56 Ba + ? + 1 30n Balance the following equations C6H14(l) + 19/2 O2(g) 6 CO2(g) + 7 H2O(l) 2 CH3NH2 (l) + 9/2 O2(g) 2 CO2(g) + 5 H2O(l) + N2(g) _______________________________________________________________________________ Consider the reaction S8(s) + 4 Cl2 (g) 4 S2Cl2(l) If 10.00 g of S8 reacts as completely as possible with 8.00 g of Cl2, how many grams of S2Cl2(l) will be formed. Show all calculations and report the answer to the correct number of significant figures. 4 mol S2Cl2 135.03 gS2Cl2 10.00 g 256.5 g mol S8 S8 mol S mol S Cl 21.06 gS Cl 2 2 S8 8 2 2 4 mol S2Cl2 135.03 gS2Cl2 8.00 g 70.90 g mol Cl2 Cl2 4 mol Cl mol S Cl 15.2 gS Cl 2 2 Cl2 2 2 2 15.2 g will be formed _______________________________________________________________________________ A compound 69.58% Ba, 6.090% C and 24.32% O. What is its empirical formula? 69.58 gBa molBa 0.507molBa 137.34 gBa 6.090 gC molC 0.507 molC 12.01gC 24.32 gO molO 1.52 molO 16.00 gO 5 CHEMISTRY 207 SAMPLE TEST QUESTIONS KEY Ba 0.507 1.0 0.507 O 1.52 3.0 0.507 C 0.507 1.0 0.507 BaCO3 ___________________________________________________________________________ How many grams of C are in 50.0 g. of Na2CO3 FW Na2CO3 = 2x22.99 + 12.01 + 3x16.00 = 105.99 g/mol mol C 12.01 gC 50.0 gNa2CO3 105.99 g mol Na2CO3 5.67 gC mol Na CO mol C Na2CO3 2 3 _______________________________________________________________________________ What is the molarity of Na2CO3 solution that is made by dissolving 2.0 g of Na2CO3 in 250.00 mL of water. 2.0 g Na2CO3 105.99 g mol Na2CO3 0.0189 mol Na CO 2 3 Na2CO3 0.0189 molNa2CO3 1000 mL 2 7.55 10 M 250 mL L _______________________________________________________________________________ What is the molarity of the solution made by diluting 25.0 mL of 2.0 M hydrochloric acid to a final volume of 1.500 L. M1V1 = M2V2 V 25.0 mL L M2 M1 1 2.0 M 0.033 M V2 1.500 L 1000 mL _______________________________________________________________________________ Write balanced net ionic equations for the following reactions. K2CO3(aq) and CuCl2(aq) Cu2+ + CO32 CuCO3(s) BaCl2(aq) + AgNO3(aq) Ag+ + Cl AgCl(s) Write a balanced nuclear equation for each of the following positron emission by 11C 11 6 C 0 11 B 1 5 6 CHEMISTRY 207 SAMPLE TEST QUESTIONS KEY alpha decay of 218Pb 218 82 Pb 4 214 Hg 2 80 Draw Lewis structures for the following compounds. Show formal charges and resonance structures if appropriate. CH3F HCN ClO3 O O Cl O + two other resonance structures ELECTRONEGATIVITIES H 2.1 Li 1.0 Be 1.5 B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Na 0.9 Mg 1.2 Al 1.5 Si 1.8 P 2.1 S 2.5 Cl 3.0 K 0.8 Ca 1.0 Ga 1.8 Ge 1.8 As 2.0 Se 2.4 Br 2.8 Rb 0.8 Sr 0.9 In 1.7 Sn 1.8 Sb 1.9 Te 2.1 I 2.5 Cs 0.7 Ba 0.9 Tl 1.8 Pb 1.9 Bi 1.9 Po 2.0 At 2.2 7